Although Taiwan is located in the subtropical area, Taiwanese are used to taking a bath with hot water no matter whether it is in hot summer or in cold winter so as to stimulate blood circulation, combat fatigue and relax their body and soul. Thus, it can be seen that water heaters become a necessity in people's daily lives. As a matter of fact, as for those people living in low-latitude area, the temperature of hot water used in bathing need not reach the standard of that in the warm and cold areas. Therefore, the Taiwanese household water heater obviously fails to bring its functions into full play. In addition, most water heaters are designed with both cold and hot water taps so the temperature of flowing water can be adjusted to suit the body requirement by means of mixing hot water generated from the water heater with cold water. It apparently increases water flow capacity but in fact causes excessive unnecessary energy waste by providing overheated water, and water resource waste by mixing overheated water. In another point, as for those who are fond of camping on mountains, it is always hard to take a hot water bath in wildness because firstly it is difficult to search water resources; secondly it is difficult to heat water; and thirdly it is easy to cause fire. Campers have to rely on camping trailers if they want to take a hot water bath, but the imported camping trailer costs several millions of dollars, which cannot be afforded by the average people. If campers want to bring household water heater by vehicle, it is required to bring the bulky and heavy gas can together. It takes time and energy to both disassemble and transport them. The journey may therefore lose its meaning and it is not feasible to travel in this way.
As mentioned above, in the present water heater market, it is lacking water heaters that are energy-saving and convenient to be brought for camping. In order to meet the demand of customers and solve the problem of inconvenient usage, this new-style multi-functional water heater, which is compact easy to be brought and low in flow capacity, is invented. It is an economic water heater with comfortable hot water, the temperature of which is suitable for a human body without mixing cold water.